1. Field of Invention
The present invention relates to a process for increasing the tension capacity of pipe piles that have been driven or drilled and grouted into the ocean floor. It also relates to apparatus for carrying out this process.
The offshore oil and gas industry is slowly moving into deeper water where their exploration and production platforms will not stand on top of rigid structures. They will float and be held in place by anchor cables or tendons attached to piling driven into the ocean floor. These driven or drilled and grouted pipe piles will be required to have large tension capacities. A piling failure by pullout during a hurricane and a dislodged production platform could result in an uncontrolled flowing oil well on the ocean floor. The process and pile assembly presented hereafter provides a new economical way to substantially increase the tension capacity of pipe piles driven into the ocean floor in deep water.
2. Description of the Prior Art
U.S. Pat. No. 4,575,282 to Pardue, Sr. et al. (1986) discloses a method of driving open end pipe piles into the ocean floor in deep water. The process uses compressed air from the ocean surface to evacuate sea water and drilling mud from the pipe pile through a one-way ball check valve and then vents the compressed air to the atmosphere. Hydrostatic pressure at depth then drives the pile.